“Because in the real world, people’s expectations can strongly influence their responses.”
Supporters of microdosing, the practice of taking very small amounts of psychedelics every few days, say that it can help to boost creativity and cognitive performance. But new research from scientists at the University of Chicago is challenging this claim.
While small amounts of LSD were shown to be safe in the placebo-controlled study published in Addiction Biology, the researchers found no evidence to support the idea that microdosing can improve cognitive performance.
Given the rising popularity of microdosing, the researchers say that more scientific study into the practice is urgently needed.
The researchers studied the effects of four low doses of LSD, given under lab conditions every three to four days. The study participants were split into three groups and given either a placebo, a low 13 microgram (μg) dose of LSD, or a higher 26 μg dose of LSD, which is still around a tenth of the strength of the average LSD dose for a typical trip.
In order to blind the study as much as possible, participants were not told that the study was about microdosing and informed that they might receive any of several drug types, including stimulants, sedatives, or hallucinogens.
“We removed any expectations that this was a psychedelic drug,” lead author Harriet de Wit, a professor of psychiatry at the University of Chicago, said in a statement. “Because in the real world, people’s expectations can strongly influence their responses.”
All of the participants were given basic cognitive and emotional task tests during each drug administration session and were additionally questioned at a drug-free follow-up appointment several days after the final drug session.
The scientists found no significant improvements in mood or cognitive performance during the drug sessions or at the follow up. Some participants who received the higher 26 μg dose reported feeling stimulant-like and LSD-like effects and were generally able to correctly guess they had been given a non-placebo drug.
Minor changes in two measures of emotional response – recognition of fearful emotions and feelings of social rejection – were also seen in some members of the 26 μg group.
These results were a surprise to the researchers, who had hypothesized they would see significant and improvements in mood and cognitive function.
“Because so many people claim to have experienced benefits from microdosing, we expected to document some kind of beneficial effect under laboratory conditions,” said de Wit.
The minor effects on emotional response were not particularly enduring and wore off by the final follow-up session, indicating that low doses of LSD do not build up in the body. The minor effects also appeared to lessen from the first to the last treatment session, which suggests that the body may start to become desensitized to its effects over time.
More investigation needed on other study populations
There are good reasons why many expect microdosing might improve mood and boost creativity; drugs like LSD directly affect the serotonin receptors in the body while also acting on other neurotransmitter systems, such as the dopamine system. But this latest evidence suggests that the effects of microdosing may be overhyped, if not negligible.
“We can’t say necessarily that microdosing doesn’t work,” de Wit said. “All we can say is that, under these controlled circumstances, with this kind of participant, these doses, and these intervals, we didn’t see a robust effect.”
She does also note several limitations on the study that may have affected its ability to assess the effectiveness of microdosing. Firstly, the participants all reported low levels of emotional distress at the beginning of the study, and so it is possible that those with a higher baseline of distress could benefit more from microdosing. The researchers also question whether microdosing effects might have more delayed therapeutic effects, like SSRIs, which would not have been detected over the length of this study.
While the researchers were surprised at this outcome of this research, other studies have also hinted that the effects of microdosing may be more down to expectancy.
Published earlier this year in eLife, a study led by researchers at Imperial College London found that participants taking placebos often reported the same beneficial effects as those given low-dose psychedelics. Similarly, those who were actually given a psychedelic but believed they had taken a placebo rarely reported improvements to their wellbeing.
“Our results are mixed,” lead author Balázs Szigeti, said in a statement following the publication of the study. “On the one hand, we observed microdosing’s benefits in a wide range of psychological measures; on the other hand, equal benefits were seen among participants taking placebos.”
“These findings suggest that the benefits are not due to the drug, but rather due to the placebo-like expectation effects.”
*This article was amended on February 21, 2022. A previous version incorrectly abbreviated the unit microgram to mg rather than μg.